eraseBetween — Delete text between boundary markers in MATLAB and RunMat.

eraseBetween(text, start, stop) removes text between two boundary markers. String/position markers, expansion rules, and 'Boundaries' option behavior follow MATLAB semantics.

Syntax

newText = eraseBetween(str, start, end)
newText = eraseBetween(str, start, end, Name, Value, ...)

Inputs

Returns

Errors

How eraseBetween works

• Accepts string scalars, string arrays, character arrays (row-by-row), and cell arrays containing string scalars or character vectors; the output keeps the same container type.
• Boundary arguments can be text or numeric positions. Both boundaries in a call must use the same representation—mixing text and numeric markers raises a size/type error.
• Text boundaries are exclusive by default: the markers are preserved while the enclosed text is deleted. Numeric positions are inclusive by default: characters at startPos and endPos are deleted together with the interior.
• 'Boundaries','inclusive' removes the markers themselves; 'Boundaries','exclusive' keeps them. The option is case-insensitive and must be supplied as name-value pairs.
• Missing string scalars propagate (the MATLAB missing placeholder in either boundary or text yields <missing> in the result). When a boundary cannot be located, eraseBetween returns the original element unchanged.
• Numeric positions are validated as positive integers, clamped to the string length, and interpreted using MATLAB’s 1-based indexing rules.

Does RunMat run eraseBetween on the GPU?

The builtin performs all work on the CPU. When any argument is GPU-resident, RunMat gathers the values first, applies the deletions on the host, and returns host-resident outputs. Providers do not need to expose device kernels, and fusion planning treats eraseBetween as a residency sink so surrounding expressions will gather automatically.

GPU memory and residency

No. RunMat automatically gathers device-resident inputs, performs the deletion on the CPU, and returns host outputs. Manual gpuArray / gather calls are unnecessary; they are honoured only for compatibility with MATLAB when you explicitly need to control residency.

Examples

Removing text between substrings

txt = "The quick brown fox";
result = eraseBetween(txt, "quick", " fox")

Expected output:

result = "The quick fox"

Deleting substrings across a string array

str = ["The quick brown fox jumps"; "over the lazy dog"];
starts = ["quick"; "the"];
ends = [" fox"; " dog"];
trimmed = eraseBetween(str, starts, ends)

Expected output:

trimmed = 2×1 string
    "The quick fox jumps"
    "over the dog"

Removing characters between numeric positions

name = "Edgar Allen Poe";
short = eraseBetween(name, 6, 11)

Expected output:

short = "Edgar Poe"

Using inclusive boundaries to drop the markers

sentence = "The quick brown fox jumps over the lazy dog";
collapsed = eraseBetween(sentence, " brown", "lazy", "Boundaries", "inclusive")

Expected output:

collapsed = "The quick dog"

Operating on character arrays while preserving padding

chars = char("Server<GPU>", "Engine<CPU>");
trimmed = eraseBetween(chars, "<", ">", "Boundaries", "inclusive")

Expected output:

trimmed =

  2×6 char array

    "Server"
    "Engine"

Preserving element types in cell arrays

C = {'alpha<1>', "beta<2>";
     'gamma<3>', "delta<4>"};
clean = eraseBetween(C, "<", ">", "Boundaries", "inclusive")

Expected output:

clean =
  2×2 cell array
    {'alpha'}    {"beta"}
    {'gamma'}    {"delta"}

Handling missing strings safely

texts = [missing, "Planner<GPU>"];
result = eraseBetween(texts, "<", ">")

Expected output:

result = 1×2 string
    "<missing>"    "Planner"

Using eraseBetween with coding agents

Open a RunMat example with live inputs, then ask the agent to explain how eraseBetween changes the result.

FAQ

Related Strings functions

Open-source implementation

Unlike proprietary runtimes, every RunMat function is open-source. Read exactly how eraseBetween is executed, line by line, in Rust.

• View the source for eraseBetween in Rust on GitHub
• Learn how the RunMat runtime works
• Found a bug? Open an issue with a minimal reproduction.

About RunMat

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